JP2003027059A - Curing agent for soil cement and manufacturing method for soil cement - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain firm soil cement even if the soil contains organic substances. SOLUTION: A curing agent for the soil cement comprises an aqueous solution which contains 8-12 wt.% of calcium chloride, 5-9 wt.% of magnesium chloride, 3-4 wt.% of potassium chloride, 3-4 wt.% of aluminum chloride, 3-6 wt.% of cobalt chloride and 65-78 wt.% of water.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hardening agent for soil cement, which is mixed in a mixture of soil, cement and water when producing soil cement which is a solidified product obtained by mixing soil, cement and water. The present invention relates to a method for manufacturing soil cement using the same.

[0002]

As a conventional hardener for soil cement, a two-component type and a powder type are known.

[0003]

However, the two-part type is expensive and the obtained soil cement is inferior in strength.

On the other hand, the powdery material has the following problems.

(1) If the soil, which is a constituent of soil cement, is an organic soil containing organic matter such as humic acid, it is difficult to cure it. Although it may be temporarily solidified, it does not have sufficient strength and tends to collapse due to aging.

This is because the active components of organic matter in the soil adsorb Ca ions of the cement in the free state, hinder the hydration reaction of the cement, and weaken the setting action of the soil particles.

For this reason, industrial waste containing a large amount of harmful substances such as organic substances and heavy metals, or aggregates such as sand, crushed particles of concrete, and incinerated ash are mixed in a mixture of soil, cement and water. Even if mixed and cured with a curing agent, industrial waste and aggregate cannot be firmly contained and held in soil cement.

(2) Since it is a powder, when it is added to and mixed with soil, cement, and water, it is difficult to sufficiently mix, the distribution of the powder becomes uneven, and the strength of the soil cement becomes uneven.

(3) The amount used is 15 to 30% by weight of the weight of cement which is a component, which is a large amount. For this reason, it is heavy and takes a large volume, and it costs a lot to store and transport it. Not only that, addition to the soil and cement and water at the site,
A large load is applied to the mixing work, resulting in poor work efficiency.

The present invention has been made in view of such conventional problems. (1) Soil which is a constituent of soil cement and the soil of cement and water contains organic substances such as humic acid. However, even if it contains organic matter such as industrial waste that mixes with soil, cement and water as other constituents, when mixed with these mixtures, the mixture of soil, cement and water becomes strong. (2) When mixed into a mixture of the constituent components of the soil cement, it can be uniformly dispersed in the soil cement to obtain a soil cement in which uneven strength does not occur partially. (3) The amount of chloride used in the cement, which is a component, is as small as 1 to 2% in terms of the amount of chloride.
(EN) It is possible to provide a curing agent for soil cement and a method for manufacturing soil cement using the same, which does not require transportation cost and can efficiently perform addition and mixing operations of a composition of soil cement to a mixture. To aim.

[0011]

The hardener for soil cement provided by the present invention is one described in the following (1) to (4).

(1) A hardener for soil cement, which is obtained by dissolving an alkaline earth metal chloride, an alkali metal chloride, an earth metal chloride, and an iron group element chloride in water.

(2) In the hardener for soil cement of the above (1), the alkaline earth metal chlorides are calcium chloride and magnesium chloride, the alkali metal chlorides are sodium chloride or potassium chloride, and the earth metal is The curing agent for soil cement whose chloride is aluminum chloride and the chloride of the iron group element is cobalt chloride.

(3) 8-12% by weight of calcium chloride,
Magnesium chloride is 5 to 9% by weight, potassium chloride is 3 to
A curing agent for soil cement, which comprises an aqueous solution containing 4% by weight, 3 to 4% by weight of aluminum chloride, 3 to 6% by weight of cobalt chloride, and 65 to 78% by weight of water.

(4) A hardener for soil cement, wherein sodium chloride and / or ammonium chloride is added to the hardener for soil cement of (3) above.

The method for producing soil cement provided by the present invention is described in the following (5) and (6).

(5) When soil, cement and water are mixed to produce soil cement, in the mixing step, the mixture of soil, cement and water is added to the above (1), (2),
A method for producing soil cement, which comprises mixing the curing agent for soil cement according to (3) or (4).

(6) In the mixing step in the method for producing soil cement according to the above (5), at least one of industrial waste, aggregate, incineration ash, and pigment is mixed into the mixture of soil, cement and water. A method for producing soil cement, which is characterized by the above.

[0019]

When a hardener for soil cement of the present invention is added to and mixed with a mixture of organic soil containing organic matter such as humic acid, cement and water, the mixture solidifies and does not easily collapse ( The reason for becoming soil cement can be explained as follows.

Humus is decomposed around the soil particles and is adsorbed in a large amount. This humus consists of humic acid as a nucleus and a molecule or atomic group formed by the binding of anions and cations. When the mixture of soil, cement and water is solidified, it is the above-mentioned humic acid that inhibits the contact between the calcium cation in the cement liquid layer and the anion on the surface of the soil particles.

When the hardener for soil cement of the present invention is added to a mixture of soil, cement and water, this reduces the dipole moment of water containing humic acid, and hydrogen ions and hydroxyl ions are split. As a result, the anions on the surface of the soil particles and the cations in the hardener for soil cement, which is an aqueous solution, and the cations in the cement liquid layer actively function and combine, and the calcium cations in the cement liquid layer and the soil particle surface The charge that impedes contact with anions is weakened (the negative action of humic acid is weakened), and the solidification phenomenon of the mixture occurs.

In this way, the hardener for soil cement exposes the surface of the soil particles, facilitates the entry of Ca ⁺⁴ between the soil particles, and prevents the dissolved component Ca ^{+4 of the} cement from spreading between the particles. make it easier.

As a result, the gaps between the particles are narrowed, and at the same time the potential is lowered, the agglomeration phenomenon of soil particles occurs. Also pH 10
The above-mentioned alkaline liquid layer is formed, and the calcium silicate hydrate generated by the hydration reaction of cement causes embryos among the soil particles to become needle crystals. As a result, the soil particles combine and the soil solidifies.

The needle-like crystals generated between the soil particles enclose the industrial waste (heavy metals therein) and the aggregate therein.
Then, the elution of heavy metals is prevented.

[0025]

BEST MODE FOR CARRYING OUT THE INVENTION [A] Field of Use of Curing Agent for Soil Cement The curing agent for soil cement according to the present invention (hereinafter referred to as curing agent) can be used, for example, in the following three fields.

(1) Solidification and stabilization of roadbed, ground, soft soil, highly organic soil, etc. (hereinafter referred to as field of use 1).

(2) Production of soil cement products containing industrial waste, aggregates, incinerated ash, pigments, etc. (hereinafter referred to as field of use 2).

The industrial wastes referred to here are, for example, construction waste materials, incinerated ash, raw conus sludge, stone sludge, metal sludge, and coal ash, and aggregates are, for example, sand, gravel, and crushed concrete particles.

Soil cement products are, for example, bricks, tiles, blocks and panels.

(3) Detoxification by solidifying contaminated soil such as soil containing industrial waste or soil contaminated with harmful (chemical) substances (hereinafter referred to as field of use 3).

[B] Preparation of curing agent The composition ratio of the curing agent used in the following examples is as follows. The composition ratio of the curing agent used in the examples was determined within the above range in accordance with the properties of the curing object.

[0032]

[Table 1] [C] Determination of amount of curing agent used The amount of curing agent used in the following examples was determined by the following procedure.

(1) The total volume of the object to be cured (soil, or soil and industrial waste, aggregate, incinerated ash, pigment, etc.) to be cured by adding and mixing cement, water and a solidifying agent is calculated.

(2) The amount of cement used with respect to the total volume of the object to be hardened is calculated according to the following formula according to the property of the object to be hardened.

Amount of cement used = total volume of hardening object × 2
0-25% (If the total volume of the object to be hardened is 1 m ³ , the amount of cement used will be approximately 200-250 kg.) (3) Based on the amount of cement used, the amount of hardener used (the amount of chloride used) , Calculate with the following formula.

Hardener usage = Cement usage x about 1-2
% (In the above example, the amount of cement used is about 200-2
Since the amount is 50 kg, the amount of the curing agent used is about 2 to 4 kg. ) [D] Outline of Examples Examples 1 and 2 below are examples of the stabilization and stabilization of the roadbed in the field of use 1. Examples 3 and 4 are examples of the manufacture of field 2 soil cement products. Although Examples of the field of use 3 are not described, they can be described in the same manner as Examples 1 to 3 according to Examples 1 to 3.

[0037]

Example 1 This example is an example in which a roadbed of a road construction site composed of organic soil containing volcanic ash soil as a main component was constructed by a road mixing method to obtain a soil cement roadbed.

The above-mentioned road mixing method does not replace the soil of the construction site, but adds a predetermined amount of cement, a hardening agent and water to the soil, mixes and stirs it, and rolls it to make a soil cement roadbed. It is a construction method.

The construction of the roadbed will be described below in the order of steps.

(1) Unevenness correction (1) The foreign matter was removed, and the unevenness of the roadbed surface was leveled and adjusted.

(2) Excavation and Scratching The roadbed with a regulated road surface was excavated by a stabilizer for about 50 cm and agitated, and stirring was repeated until the soil was pulverized.

(3) Unevenness rectification (2) The soil layer powdered by stirring was leveled with a bulldozer and temporarily rolled with a tire roller.

(4) Dispersion of Cement About 200 kg of cement was sprayed per 1 m ^{3 of} soil on the roadbed subjected to temporary rolling.

(5) Mixing and mixing the cement with stirring, so that both the cement and the soil are sufficiently mixed.
Mixing was repeated 3 times or more with a stabilizer.

(6) Scattering of the curing agent The soil in which the cement was uniformly mixed was uniformly impregnated with the curing agent having the composition ratio shown in Table 2 by hand spreading. The amount of the hardener applied (use amount) was set to about 1% of the amount of cement used. That is, 2 kg, which is 1% of a small amount of cement of about 200 kg
And

[0046]

[Table 2] The water content ratio of the soil after the application of the curing agent was set to "slightly heavy", that is, a slump value of about 2 to 4, and was set to such a degree that the soil after application was not tattered when the soil was held by hand.

(7) Stirring Mixing of Soil, Cement and Solidifying Agent The mixture of soil and cement impregnated with the solidifying agent was repeatedly stirred and mixed three times with a stabilizer.

(8) Uneven shaping (3) The mixture of soil, cement and solidifying agent is leveled with a grader,
The smoothness of the leveling surface was obtained and the slope was determined.

(9) Compaction and finish rolling compaction The roadbed with smoothness was determined by using a vibrating rammer, and then compacted by tire rollers. The compaction was performed within 2 hours after spraying the solidifying agent.

(10) Water sprinkling and curing finishing After the rolling compaction was completed, water was sprinkled by hand sprinkling on the roadbed that had been compacted within 4 to 6 hours. After watering, it was cured for about 24 hours. After curing, passenger cars could pass through.

[0051]

Example 2 In this example, a roadbed of a road construction site composed of a humus soil, an organic soil containing gravel and sand as a main component was constructed by a mixing rolling method to be a soil cement roadbed.

The mixing compaction method referred to here is that the soil at the construction site is plowed off by the amount corresponding to the thickness to be hardened,
This is a method in which cement and a solidifying agent are added to the soil and mixed, and the resulting mixture is cast on a roadbed and uniformly rolled to finish into a soil cement roadbed.

The construction of the roadbed will be described below in the order of steps.

(1) Unevenness correction The foreign matter was removed, and the unevenness of the roadbed surface was leveled and adjusted.

(2) Excavation and plow-off 20 cm thick to be hardened from the roadbed that has been unevenly rectified
Excavate a considerable amount of soil with a hand dozer, remove the plow,
Prepared for mixing by gathering near the mixer which was made to stand by in advance.

(3) Roadbed unleveling and rolling compaction The grader was used to carry out unleveling conditioning of the roadbed after the removal of the spade, and rolling vibration was performed using a vibrating roller. The unleveling and the rolling compaction are performed so that the roadbed mixture prepared in the mixing step described later can be uniformly cast with a predetermined construction thickness.

(4) Water sprinkling Water was sprayed on the roadbed on which the road surface had been flattened and compacted, until it was saturated with the tire roller engine sprayer.

This step is for facilitating the mixture of the roadbed mixture obtained in the later-described mixing step into the roadbed when the mixture is poured into the roadbed. Fulfills the adhesive function of.

(5) An organic soil of the road construction site, gravel and crushed stone for soil condition adjustment were put into a mixing mixer and mixed to obtain a soil condition mixture. The input amount of gravel and crushed stone was set to about 10% of the organic soil (note that if the soil for road construction is highly viscous soil, 10% or more of mountain sand or river sand is usually added and mixed).

Then, cement and a hardening agent were added to the obtained soil-conditioning mixture in this order, and they were mixed to prepare a roadbed mixture.

The amount of cement (the amount used) was about 220 kg per 1 m ^{3 of the} roadbed mixture. Further, as the curing agent, the one having the composition ratio shown in Table 3 was used, and the usage amount was about 2% of the cement usage amount. That is, it was set to 4.4 kg, which is 2% of the amount of cement used of about 220 kg. The slump value was about 3.

[0062]

[Table 3] (6) Laying and leveling (placing) The mixture for the roadbed prepared by mixing was laid and leveled (casting) on the roadbed in a wet state by spraying with water, and smoothed with a grader to give a gradient.

(7) Compaction and Finish Rolling The roadbed mixture was laid and leveled, and within 2 hours, it was first compacted with a Macadam roller, and then rolled with a tire roller to form a roadbed. .

(8) Sprinkling and Curing Finish The roadbed formed by rolling and rolling was sprinkled with tire rollers within 4 to 5 hours after rolling and then cured for about 4 hours. Four hours later, cars were allowed to pass.

[0065]

[Embodiment 3] This embodiment is an example in which a block of soil cement is manufactured by mixing red clay of Okinawa, incinerated ash of construction waste, crushed concrete particles, cement and a hardening agent and hardening them. .

The manufacture of this block will be described below in the order of steps.

(1) Mixed red soil, incinerated ash of construction waste, and crushed concrete particles were put into a mixer at a volume ratio of 3: 1: 1 and mixed thoroughly to prepare a mixture of about 1 m ³ .

(2) Addition of cement and hardening agent and kneading The cement and hardening agent were added to the obtained mixture in this order, and they were sufficiently kneaded to prepare a kneading material for blocks.

The amount of cement input (the amount used) was
About 250 kg per m ³ . Further, as the curing agent, the one having the composition ratio shown in Table 4 was used, and the usage amount was about 2% of the cement usage amount. That is, the amount of cement used is about 25
It was set to 5 kg, which is 2% of 0 kg. Water was appropriately added and adjusted so that the slump value was about 2.

[0070]

[Table 4] (3) Molding The prepared block kneaded material was filled in a block mold within 1 hour and molded.

(4) After 5 hours from the dry molding, the block was taken out from the mold and taken out. The obtained block was harder than an ordinary concrete block and could not be easily collapsed even when hit hard with a hammer.

[0072]

[Embodiment 4] This embodiment is an example in which bricks of soil cement are manufactured by mixing and curing red soil, incinerated ash of industrial waste, raw consludge, cement, and a curing agent.

The manufacture of this brick will be described below in the order of steps.

(1) The mixed red soil and green conus sludge were put into a mixer at a volume ratio of 2: 1 and mixed thoroughly to prepare a mixture of about 1 m ³ .

(2) Addition and Kneading of Cement Hardener Cement and hardener were added to the obtained mixture in this order, and they were sufficiently kneaded to prepare a brick kneaded product.

The amount of cement input (the amount used) was
About 250 kg per m ³ . The curing agent is shown in Table 5.
The composition ratio was used, and the amount used was 5 kg, which is 2% of the cement amount used 250 kg. Water was appropriately added and adjusted so that the slump value was about 2.

[0077]

[Table 5] (3) Molding The prepared kneaded product for bricks was filled into a brick mold within 1 hour and molded.

(4) After 5 hours from the dry molding, the brick was taken out by demolding. The obtained bricks were comparable in strength and color tone to those of ordinary bricks.

[0079]

As described above, according to the curing agent for soil cement of the present invention, since it is an aqueous solution of chlorides obtained by dissolving the above-mentioned various chlorides in water, the following effects are obtained. Play.

(1) Even if the soil, which is a constituent of soil cement, and the soil of cement and water, contains organic substances such as humic acid, it is mixed in the soil, cement, and water as other constituents. Even if the industrial waste contains organic substances, if the curing agent of the present invention is mixed in the mixture,
This exposes the surface of the soil particles, facilitates the entry of Ca ⁺⁴ between the soil particles, and facilitates the dissolution component Ca ^{+4 of the} cement to spread between the particles.

Therefore, even if the hardener of the present invention is soil containing organic matter, it can be made into hardened soil cement by adding and mixing it with cement.

(2) Since the hardening agent of the present invention enables the formation of a strongly hardened soil cement as described above, it is possible to add industrial waste, aggregates, incinerated ash, various sludges, etc. to the soil cement. If waste materials are mixed in advance, it will be possible to reuse these waste materials to manufacture soil cement products such as bricks, tiles, blocks, and panels.

(3) The curing agent of the present invention can be used in a small amount of 1 to 2% in terms of chloride content with respect to cement, which is a component of the composition. Therefore, storage and transportation costs are low, and soil is not used. It facilitates addition and mixing of cement components to the mixture.

(4) When the hardener of the present invention is mixed in a mixture of the constituents of soil cement, it is uniformly dispersed therein, and enables formation of soil cement in which uneven strength does not occur partially.

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Claims (6)

[Claims] 1. A curing agent for soil cement, which comprises dissolving an alkaline earth metal chloride, an alkali metal chloride, an earth metal chloride and an iron group element chloride in water. 2. The alkaline earth metal chlorides are calcium chloride and magnesium chloride, the alkali metal chlorides are sodium chloride or potassium chloride, the earth metal chlorides are aluminum chloride, and iron group elements. The curing agent for soil cement according to claim 1, wherein the chloride is cobalt chloride. 3. Calcium chloride 8-12% by weight, magnesium chloride 5-9% by weight, potassium chloride 3-4% by weight, aluminum chloride 3-4% by weight, cobalt chloride 3-6% by weight, A hardening agent for soil cement, which comprises an aqueous solution containing 65 to 78% by weight of water. 4. The curing agent for soil cement according to claim 3, wherein sodium chloride and / or ammonium chloride is added. 5. The soil cement according to claim 1, 2, 3 or 4, which is a mixture of soil, cement and water when the soil cement is produced by mixing soil, cement and water. A method for producing soil cement, which comprises mixing a curing agent for use in soil. 6. The soil according to claim 5, wherein in the mixing step, at least one of industrial waste, aggregate, incineration ash, and pigment is mixed into the mixture of soil, cement, and water. Cement manufacturing method.